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Review of Impala 27


Impala 27
Impala 27 anno 1982.


Basic specs.

sail specifications
The Impala 27 is a sailboat designed by the Danish maritime architect E. Bjørn Jensen in the early eighties. The Impala 27 is built by the Danish yard Tåsinge Glasfiber A/S.

Looking for a new boat? Find a Impala 27 or similar boat for sale

Hull
The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.

Interior
Interior
Interior of Impala 27 anno 1982.
The interior is like many other boats made of mahogany.
The boat is equipped with 5 berths, a galley and toilet facility.
Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.
Front cabin
Front cabin of Impala 27 anno 1982.
Galley
Galley of Impala 27 anno 1982.
Bathroom
Bathroom of Impala 27 anno 1982.

Cockpit
Cockpit
Cockpit of Impala 27 anno 1982.
Rig
Rig
Rig of Impala 27 anno 1982.
The boat equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a genaker or a spinnaker for optimal speed.

Keel
Keel
Keel of Impala 27 anno 1982.

The Impala 27 is equipped with a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.

The keel is made of iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

Impala 27 can enter most marinas as the draft is just about 1.65 - 1.75 meter (5.41 - 5.71 ft) dependent on the load. See immersion rate below.


Engine
Motor
Impala 27 anno 1982.

The boat is typically equipped with an inboard diesel engine.


Sailing characteristics

This section covers widely used rules of thumb to describe the sailing characteristics. Please note that even though the calculations are correct, the interpretation of the results might not be valid for extreme boats.

Stability and Safety

What is Capsize Screening Formula (CSF)?

The capsize screening value for Impala 27 is 2.33, indicating that this boat would not be accepted to participate in ocean races.


Theoretical Maximum Hull Speed

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.4 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.


Immersion rate

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Impala 27 is about 145 kg/cm, alternatively 814 lbs/inch.
Meaning: if you load 145 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 814 lbs cargo on the boat it will sink 1 inch.


Sailing statistics

This section is statistical comparison with similar boats of the same category. The basis of the following statistical computations is our unique database with more than 26,000 different boat types and 350,000 data points.

Motion Comfort Ratio

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Impala 27 is 14.6 - 15.2.

Low High 18% 0 50 100
Comparing this ratio with similar sailboats show that it is more comfortable than 18% of all similar sailboat designs. This is a comfort value significantly below average.


L/B (Length Beam Ratio)

What is L/B (Length Beam Ratio)?

The l/b ratio for Impala 27 is 2.69.

Slim Wide 86% 0 50 100
Compared with other similar sailboats it is more spacy than 86% of all other designs. It seems that the designer has chosen a significantly more spacy hull design.


Ballast Ratio

What is a Ballast Ratio?

The ballast ratio for Impala 27 is 42%.

Low High 58% 0 50 100
This ballast ratio shows a righting moment that is higher than 58% of all similar sailboat designs. A righting moment (ability to resist heeling) just above average.


D/L (Displacement Length Ratio)

What is Displacement Length Ratio?

The DL-ratio for Impala 27 is 190 which categorizes this boat among 'light racers'.

Heavy Light 73% 0 50 100
73% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.


SA/D (Sail Area Displacement ratio)

What is SA/D (Sail Area Displacement ratio)?

The SA/D for Impala 27 with ISO 8666 reference sail is 20.4, with a 135% genua the SA/D is 23.9.

Low High 92% 0 50 100
The SA/D ratio indicates that it is faster than 92% of all similar sailboat designs in light wind.


Over- / underrigged

Low High 86% 0 50 100
The Impala 27 has more rig than 86% of all similar sailboats, which indicates that the boat is significantly overrigged.


RSP (Relative Speed Performance)

What is Relative Speed Performance?

The Relative Speed Performance for Impala 27 is 93

Slow Fast 93% 0 50 100
The relative speed performance is 93 which means that a it is faster than 93% of all similar sailboat designs.


Maintenance

Bottom Paint

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 25m2 (269 ft2).
Based on this, your favourite maritime shop can tell you the quantity you need.

Note: If you use a paint roller you will need more paint than if you use a paintbrush.


Rig

Dimensions of sail for fractional rig.

mainsail specifications genoa specifications spinnaker specifications

Are your sails worn out? You might find your next sail here: Sails for Sale



If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.



Guiding dimensions of running rig
UsageLengthDiameter
Mainsail halyard 27.8 m(91.2 feet)8 mm(5/16 inch)
Jib/genoa halyard27.8 m(91.2 feet)8 mm(5/16 inch)
Spinnaker halyard27.8 m(91.2 feet)8 mm(5/16 inch)
Jib sheet 8.3 m(27.4 feet)10 mm(3/8 inch)
Genoa sheet8.3 m(27.4 feet)10 mm(3/8 inch)
Mainsheet 20.9 m(68.5 feet)10 mm(3/8 inch)
Spinnaker sheet18.4 m(60.3 feet)10 mm(3/8 inch)
Cunningham3.5 m(11.5 feet)8 mm(5/16 inch)
Kickingstrap7.0 m(23.0 feet)8 mm(5/16 inch)
Clew-outhaul7.0 m(23.0 feet)8 mm(5/16 inch)

Boat owner's ideas

This section shown boat owner's changes, improvements, etc. Here you might find inspiration for your boat.

Do you have changes/improvements you would like to share? Upload a photo and describe what to look for.



Finally

We are always looking for new photos. If you can contribute with photos for Impala 27 it would be a great help.

If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.



References